1. Field of the Invention
This invention relates to hard space suit joints, especially for the elbow and knee. It may also be used on diving suits, manipulator arms, user-occupied arms for penetrating boxes such as autoclaves, high vacuum boxes for integrated circuit work and the like, and to cover and isolate articulated torque drives which require protection from hostile environments. The joint has an outer covering of a relatively rigid material comprising three serially-connected sections wherein the outer two sections rotate in unison in a direction opposite to the inner section so that the joint flexes as does a normal elbow or knee joint.
2. Description of the Prior Art
U.S. Pat. No. 3,405,406 (and particularly FIGS. 6-11) shows an elbow or knee joint that comprises two rotatable sections. The present invention provides a joint which permits a smaller envelope size.
U.S. Pat. No. 4,091,464 (particularly FIGS. 10, 11, 16 and 17) also reveals elbow and knee joints that may be used in a pressurized suit. The present invention provides much greater flexibility of movement at the joint and obviates the need for pleated or rolling convolute diagrams. U.S. Pat. No. 3,421,158 also discloses a rolling convolute variety elbow joint. The joint has five nesting sections that are sealed by means of a fabric that must be rolled back and forth when the joint is extended and flexed. The joint has three pivot points whereas the present invention only has one (as does the human elbow).
U.S. Pat. No. 3,712,481 discloses a snakelike actuator for use on submarines and so forth that is motor actuated, whereas the present invention requires no motors and is actuated by body movement of the wearer. The snakelike actuator arm comprises a continuous bellows outer layer which provides a hermetic seal plus two inner layers, each of which comprises alternate cylindrical wedges and bellows. In a second embodiment the actuator arm comprises three bellows layers plus a layer of rotatable wedges. In each instance the arm is moved by means of torque motors coupled to the layers.
The paper "High-Pressure Protective System Technology" by Hubert C. Vykukal and Bruce W. Webbon, ASME Publication 79-ENAs-15, 1979, includes a photograph (FIG. 6) of a mockup of a portion of a spacesuit. The mockup comprises a torso section, a single arm and glove, and a partial head cover. The elbow joint comprises three independently rotatably sections. The included angle between the ends of the center section is larger than the included angles associated with the end sections. Inasmuch as the joint was prone to lockup it was abandoned and not employed in an actual pressurized suit. Lockup is a condition whereby the joint will not permit desired planar motion without additional programming (or possibly not at all).